Fuel pump



May 20, 1941.

v s. JENCICK FUEL PUMP Filed Sept. 29,. 1938 2 Sheets-Sheet 1 INVENTORQ I 7PH- JZwc/c/c jaw w of W ATTORNEY}? May 20, 1941. VQS.JENCICK 7 2,242,582

' FUELPUMPV 7 Filed Sept. 29, 1938 2 She'ts-Sheet 2 INVENTOR. draws/v Jwc/c/r ATTORNEYS Patented May 20, 1941 Stephen Jencick, Chagrin Falls, Ohio, assignor of two-fifths to Leo L. Williams, Cleveland Heights,

Ohio

Application September 29, 1938, Serial No. 232,363

4 Claims. (Cl. 103-150) This invention relates to pumps and more particularly to a diaphragm pump of improved and simplified construction which is especially suitable for use in the fuel supply systems of motor vehicles.

An object of my invention is to provide a fuel pump of improved and simplified construction having highly desirable operating characteristics, such that the fuel supply at the carburetor nozzle or jet can be maintained at a substantially constant head throughout widely varying conditions of operation of the vehicle Another object of my invention is to provide an improved pump ofthe diaphragm type having an elastic diaphragm which is adapted to yield under the influence of abnormal pressure or vacuum in the pump casing whereby a sensitive self-regulation of the pumping action can Yet another object of my invention is to y rovide an improved fuel pump having an intake chamber or reservoir in which a vacuum can be maintained for preventing the fuel in the supply line from draining back into the storage tank, thus insuring an immediate supply of fuel at the pump at all times.

Another object of my invention is to provide an improved vehicle fuel pump having adjustable means for regulating its delivery capacity whereby the pump is adapted to serve as a speed governor for the vehicle.

My invention may be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and more particularly set out in the appended claims.

In the accompanying sheets of drawings Fig. 1 is a top plan view of a pump embodying my invention;

'Fig. 2 is a vertical sectional view taken through the pump as indicated by the section lines 2-2 of Fig. 1 and illustrating theconstruction and manner of operation;

3 is a transverse sectional view taken through the pump on line 3-3 of Fig, 2;

Fig. 4 is a partial transverse sectional view taken on line 44 of Fig. 2

Fig- 5 is another partial transverse sectional view, on a larger scale, taken on line 5-5 of Fig. 2;

Fig. 6 is a detached through the diaphragm;

.Fig. 7 is a partial vertical sectional view taken through a modified form of diaphragm and the clamping portions of cooperatmg housing sections; and a Fig. 8 is a similar sectional view but showing the diaphragm stretched and the housing secsectional view taken tions in clam-ping engagement therewith.

For the purpose of describing the construction and operation of my improved pump 'more in detail, further reference will now be made to the drawings, but before proceeding with such more" detailed description it should be understood that my invention is not limited to the construction, manner of operation, or specific use of the particular pump herein disclosed but may be embodied in various other similar devices coming within the scope of the appended claims.

As shown in Figs. 1 and ,2 my improved pump is of the diaphragm type having, in this instance, the diaphragm l0 and a housing formed of sections II and I2 and containing the chambers l3 and H. The housing sections II and I2 may be formed of cast metal or any other suitable material and may be connected by screws I5, with the diaphragm assembled therebetween in a manner to be explained more fully hereinafter. The housing section II has fluid supply and discharge pipes or conduits I6. and I1 connected therewith and through which the gasoline or other fluid flows to and from the pump. The housing'section I! may have an attaching portion or bracket I8 for cooperation with an available part of the vehicle structure for mounting the pump thereon, a I

The housing section -Il may be constructed with recesses in the top and bottom thereof for forming the chambers l3 and I4 and with a transverse wall portion 19 extending between such recesses. A cover 20 of cup-like shape, and which may be formed of a transparent substance or any other suitable material, may be mounted on the top'of the housing section II to complete the chamber l3. This chamber forms an intake chamber or reservoir to which the fuel is supplied by the pipe l6. As will be hereinafter explained, a partial vacuum may be maintained in the chamber 13 and for this reason this chamber may at times be referred to as a vacuum chamber.

' The cover 20 may be retained in place on the housing section Ii by the annular bead 2| of the latter and by the clamping screw or wing bolt 22. The bolt 22 may extend through .the cover and may have threaded engagement with the wall portion 19, or as in this instance, with a hollow member or valve seat 23 mounted on such wall portion. A gasket 24 may be provided between the cover 20 and the housing section II and a packing washer 25 may be used between the cover and the head of the wing bolt 22.

The diaphragm i extends transversely of the housing section I I to close the lower recess thereof and complete the chamber I4. This chamber is the working chamber of the pump which is expanded and contracted in volume by flexing or moving of the diaphragm l0 whereby fluid is drawn into the pump through the supply connection I6 and expelled therefrom through the discharge connection IT.

The housing section Il may have an upright inlet passage or bore 26 therein of which the upper end communicates with the chamber 13 a substantial-distance above the bottom or wall portion l9. At a lower point thereof the bore 26 is in open communication with the supply pipe I6 through the lateral supply passage or port 21. Fluid entering the chamber 13 through thepipe i6 and the bore 26 passes downwardly from the hollow member 23 and the passage 28 of the wall portion l9 into the working chamber l4. The member 23 maybe a plug-likemember which is screwed into a threaded recess of the wall portion I9 and may have openings 29 therein which communicate with the chamber I3 adjacent the bottom thereof. The flow of fluid downwardly through the passage 28 into the chamber l4 may be controlled by a check valve 30 which is normally held in seating engagement with the lower end of the member 23 by a compression spring 3|.

A discharge passage or recess 36 may be formed in the wall portion IQ of the housing section II to accommodate a check valve 31 and to connect the discharge pipe H with the working chamber 14. A bushing 38 may be screwed into the lower end of the recess 36 to form a seat against which the valve 3'! is normally pressed by the compression spring 40. The opening of the bushing provides a communicating passage 4| leading into the working chamber l4.

' The diaphragm l0 forms a portion of the wall of the working chamber l4 and when moved or flexed causes variation in the volume of this chamber to produce a pumping action. In my improved pump the diaphragm is of novelform and produces operating characteristics not heretofore obtainable in fuel pumps of the diaphragm type. This diaphragm is formed of an elastic rubber-like material, such as synthetic rubber, or any other suitable elastic substance which will withstand the deteriorating effects of gasoline or other liquid fuels to be pumped. The diaphragm may be in the form of a disk having a central portion adapted to be clamped between the cooperating cup-shaped sheet metal clamping members 43 and 44 and may have an outer or marginal portion adapted to be clamped or held between the cooperating portions of the housing sections II and 12. The portion of the elasticity and flexibility of the diaphragm and otherwise improve its characteristics and suitability for use in a fuel pump.

The elasticity of the diaphragm I0 is a very I important characteristic of this member because it enables the pump to operate with a self-regulating action whereby a desired predetermined head of fuel can be more accurately maintained yield in response to abnormal or excessive pressure or vacuum conditions existing in the chamber or chambers of the pump. When the pressure in the working chamber l4 increases the diaphragm yields, that is, stretches and bulges downwardly and prevents the pressure increase from immediately causing an excessive amount of fuel to be delivered into the pipe ll. On the other hand, a vacuum condition occurring in the chamber I4 will tend to cause the diaphragm to yield and bulge upwardly and this will reduce the volume of the working chamber thereby enabling the pump to maintain a desired pressure-in the discharge pipe H. The elasticity of the diaphragm also permits energy to be stored therein during one portion of the stroke and to be expended during another portion of the stroke whereby pulsations in the pump discharge can be more or less eliminated.

I have observed that a diaphragm formed of rubber-like material or other substances suitable for hydrocarbon fuel pump diaphragms are usually subject to more or less swelling as the result of the action of the fuel thereon. Such swelling of the diaphragm material is apt to cause undesirable variation in the operation of the pump. I find. that the undesirable effects of such swelling of the diaphragm material can be largely overcome by' assembling my pump so that the diaphragm I0 is in an initially stretched or tensioned condition. When the pump is assembled with the diaphragm in such a stretched condition the subsequent swelling of the diaphragm material, which may result from the action of the fuel thereon, will cause very slight change, if any; in the operating characteristics of the pump.

To facilitate the assembling of the pump with the diaphragm ill in such an initially stretched condition, I construct one or both of the housing sections H and I2 with an annular groove 46 in the diaphragm engaging portion thereof and provide the diaphragm with an annular bead 41 of smaller diameter but adapted to engage in such groove or grooves when the diaphragm is stretched. In the assembly operation the housing sections II and I2 are pressed together with the diaphragm therebetween and with the bead 41 of the diaphragm engaging.

'for at least a portion of its circumference, in

the grooves 46. The diameter of the bead 41 being somewhat less than the diameter of the grooves 46 does not freely engage itself therein, but by relative rotation of the housing sections with pressure applied thereto the bead of the diaphragm can be subjected to a wedging action which will result in the diaphragm being stretched or tensioned as the bead shifts into the grooves. After the bead of the diaphragm has been thus engaged in the grooves the housing sections may be clamped together by the screws l to hold the diaphragm inthe desired initially stretched or tensioned condition. The corrugations 45 increase the flexibility and elasticity of the diaphragm, as mentioned above, and thus also facilitate the stretching or tensioning of the diaphragm at assembly of the pump. In addition to serving as a means for stnetcliing the diaphragm duiring the assembling operation the bead 41 cooperates with the housing sections to provide a fluid tight seal around the edges of the diaphragm.

It is not necessary that the housing sections, or either of them, be provided with an annular groove to receive the diaphragm bead because the diaphragm can be assembled in an initially stretched condition between housing sections having solid clamping portions 450, as shown in Figs. 7 and 8. When the housing sections have such solid clamping portions the bead 41a of the diaphragm Illa has relatively steep angular or beveled annular faces 41b against which the outer edges of the housing sections exert a wedglng action as their clamping portions are-brought together. The diaphragm is made of such diameter that this wedging action will cause it to be stretched laterally, as indicated in Fig. 8.

Although I have described the elastic diaphragm as being a very desirable feature in a fuel pump, it should be understood that this feature is not restricted in utility to fuel pumps but is also desirable in vacuum pumps and in pumps for handling various fluids.

For actuating or flexing the diaphragm l0, motion may be transmitted from any available moving. part of the vehicle, such as the cam shaft 48. A push rod 48 cooperating with the cam face 50 is reciprocated to cause swinging movement of a bell crank lever 5| which is pivoted in the housing section It. A second bell crank lever 52 may be pivoted in the housing section I! to receive motion from the bell crank lever 5| and to cause reciprocation of a plung er 53. This plunger may be guided in an opening 54 of the housing section l2 and may have its upper end connected with the clamping members 43 and 44 for imparting upward movement .to subsequently cause a return movement of the diaphragm.

My improved fuel pump also embodies a valvecontrolled by-pass 56 through which fluid may be returned from the working chamber l4 to the supply passage 21. The passage or port 58 may be formed in the wall portion l9 and is normally closed by a check valve or relief valve contained in the upwardly extending bore or inlet passage 26. This valve may comprise a ball 51 and a compression spring 58 acting thereon to normally hold the ball seated. A hollow screw or bushing 58 mounted in the upper end of the passage 26 forms a seat and guide for the upper end of the spring 58. The opening through this bushing forms a port or fluid connection between the passage 26 and the chamber l3.

In addition to the valve 51 serving as a relief valve I may use this valve for regulating the delivery capacity of a vehicle fuel pump so as to enable the pump to act as a governor for limiting or controlling the speed of the vehicle to a predetermined maximum value. This may be especially desirable in fuel pumps for motor adjustment of the tension of the valve spring 58 trucks, taxicabs and other vehicles. To this end I provide for a step-by-step or predetermined so that by permitting more or less fuel to be returned to the supply passage 21 the delivery capacity of the pump can be regulated to a value corresponding with the maximum or desired speed for the vehicle.

This adjustment of the spring 58 may be made by screwing the bushing 59 in or out of the threaded upper portion of the passage 28. When the desired adjustment has been made the bushing may be held against accidental or unauthorized shifting as by a wire seal 56a. For this purpose the housing section II may have a flange portion 510. adjacent the upper end of the passage 26 and provided with spaced openings 56b which indicate the different adjustments for. the bushing and accommodate the seal 55a. The bushing may have a lug or car 59a thereon which serves as a pointer and is provided with an opening to accommodate the seal.

It will be noted that the supply passage 21 extends at substantially right-angles to the upwardly extending bore or inlet passage 25 and communicates with th latter at a point just above the valve-controlled .by-pass 56. With this arrangement it will be seen'that the passage 56 will direct the by-passed fuel upwardly as a jet 1 across the open end of the supply passage 21 and this jetwill tend to produce a vacuum or sue-- tion in the supply passage 21 which will prevent the fuel from draining out of the supply pipe 18 back into the fuel tank. Thus the supply pipe l6 and passage 21 will always be maintained full of a solid body of liquid fuel ready to' be immepassage 26 into the vacuum chamber I3. The I fluid is drawn downwardly past the valve 38 into the working chamber I4 and is then forced past the check valve 31 into thedischarge pipe I1 which carries'the fuel to the carburetor or other desired point. If the delivery pipe I1 is closed as by closure of the float valve of the carburetor, or if the delivery capacity of the pump exceeds the rate 'of consumption, the pressure in the working chamber l4 will increase and upon reaching a predetermined value will lift the valve 51v and cause fluid to be returned to the supply passage 21. A partial vacuum is always maintained in the chamber l3 and this prevents the fuel in the pipe I6 from draining back into the fuel tank of the vehicle and thus the fuel supply line remains filled or charged so that fuel will always be immediately available at the pump. The valves 30, 31 and 51 afiord self-regulating pumping action whereby the pressure or head in the discharge line I1 can be maintained approximately constant. The elasticity of the diaphragm i0 supplements the regulating action of these valves by permitting a yielding-or bulging oi the diaphragm in response to excessive pressure or vacuum. conditions in the pump. Such elasticity of the diaphragm affords a more sensi-' tive self-regulating action whereby the pressure or head in the discharge line 11 can be maintained more nearly constant than would be possible by means of the valves alone.

From the foregoing description and accompanying drawings it will now be readily seen that I have provided an improved fuel pump of simple construction, but which is highly eflicient in operation and is capable of accurately maintaining a desired head or pressure in the discharge line. It will be seen furthermore that the vacuum chamber and valve arrangement contribute to this desired and and also maintain the supply line charged with fluid so that an instantaneous delivery of fuel can be had and initial idle strokes of the pump can be avoided. The adjustable relief or by-pass'valve permits the delivery capacity of the pump to be regulated to correspond with a desired maximum speed for the vehicle. Moreover, it will be seen that the elasticity of the diaphragm substantially eliminates pulsation in the discharge stream and provides for a more accurate and sensitive selfregulating operation of the pump. Furthermore the assembly of the diaphragm under initial tension eliminates undesirable variations in operation heretofore resulting from swelling and other deteriorating efiects of the fuel on the diaphragm material.

While I have illustrated and described the improved fuel pump of my invention in a somewhat detailed manner it will be understood of course that I do not wish to be limited to the details of construction and arrangements of parts herein disclosed, but regard my invention as including such changes and modifications as do not constitute a departure from the spirit of the invention and the scope of the appended claims.

Having thus described my invention, I claim:

1. In a pump of the diaphragm type, a pair of housing sections having cooperating annular clamping portions, and an elastic diaphragm held between said housing sections in an initially stretched condition, said diaphragm having thereon an annular bead provided with oppositely beveled faces and being of a diameter to be wedgingly engaged by said portions for causing stretching of the diaphragm as said portions are brought into clamping cooperation therewith.

2. In a pump of the diaphragm type, a housing section having a recess therein and a clamping portion surrounding said recess, a second housing section having a clamping portion for cooperation with the clamping portion of the first housing section, one of said clamping portions having an annular groove therein, and a diaphragm extending transversely of the recess and having thereon an annular bead the initial diameter of which is smaller than the diameter of said groove and which is adapted to be pressed into said groove by the cooperation of said clamping portions, said diaphragm being elastic and subjected to stretching upon assembly with the housing sections.

3. In a liquid fuel pump, a housing having a vacuum chamber and a working chamber therein, a fuel inlet passage extending upward in said housing and opening into the vacuum chamber a substantial distance above the bottom of the latter, a fuel supply passage extending substantially normal to the direction or said inlet pas-' sage and opening into the latter, a diaphragm forming a portion of the wall of the working chamber, means for moving the diaphragm for expanding and contracting the working chamber, a discharge connection leading from the working chamber and having a check valve therein, a passage connecting the vacuum chamber with the working chamber and having therein a check valve opening toward the latter chamber, and a check-valve-controlled by-pass connecting the working chamber with said inlet passage and arranged to direct by-passed fuel across the opening of said supply passage.

4. In a pump of the diaphragm type, a housing having therein a working chamber and intions, the diaphragm being also elastic and yield able by stretching to abnormal pressureand being assembled with the housing so as to be in an initially stretched condition.

a STEPHEN JENCICK. 

